The invention relates to open flame resistant mattresses and mattress foundations protected by a fire barrier/thermally insulating fabric.
The importance of preventing mattress fires in institutional settings has been recognized for many years, and a number of standards for flame retardance of these mattresses have been promulgated. A federal performance standard applicable to mattresses on a nationwide basis is codified in 16 CFR Part 1632 (Standard for Flammability of Mattresses and Mattress Pads), customarily referred to as the Cigarette Ignition Standard, the entire contents of which are incorporated herein by reference. However, even when mattresses meet the requirements of the Cigarette Ignition Standard, these can react with volatile and potentially deadly results when exposed to open-flame and smoldering ignition sources. The result can be a fire with sufficient energy to cause an average size room to reach a state of total instantaneous combustion or flashover. The California Bureau of Home Furnishings and Thermal Insulation has addressed the hazards associated with the ignition of mattresses in public institutions with California Technical Bulletin #129 (hereinafter xe2x80x98TB 129xe2x80x99), published as a draft standard in 1992. It has since been adopted as a voluntary consensus standard by the American Society of Testing and Materials as ASTM E-1590 and the National Fire Protection Association (NFPA) as NFPA 267. (ASTM E-1590 and NFPA 267 use essentially the same test protocol as TB 129 but contain no failure criteria.) The standard has also been embodied in NFPA""s Life Safety Code 2000, section 10.3.4, and in Underwriter""s Laboratories"" UL 1895.
Although hazards in public institutions have been addressed with standards based on TB 129, the number of injuries and fatalities associated with residential fires in which a mattress was the first item ignited or the mattress exacerbated the fire event has led to efforts to reduce flammability of mattresses used in homes. One notable event is the passage of Assembly Bill 603 in the California Legislature of Assembly. The bill calls for virtually all mattresses and sleep surfaces sold in the State of California, as of Jan. 1, 2004 to meet an open flame resistance standard. In addition, the Consumer Products Safety Commission is currently developing new regulations for further reducing mattress flammability beyond the level required by the Cigarette Ignition Standards. This was announced recently in the Federal Register (Advance Notice of Public Rule Making (ANPR) published Oct. 11, 2001)).
New standards for flammability of residential mattresses will require new materials and methods of manufacturing these, as mattresses targeted for residential markets differ significantly from those typically used in institutions. Institutional bedding installations typically require only a mattress and no foundation; mattress may be simply a solid core of polyurethane foam, which may be combustion modified to some degree as well. Many of the components used in institutional mattresses and sleep support surfaces, including fill materials and covering fabrics are subject to performance testing according to test criteria such as NFPA 701 and California Technical Bulletin No. 117.
In contrast to institutional bedding, residential sleep surfaces are typically covered and filled with a number of potentially volatile components, including polyurethane foam, highly combustible ticking fabrics, insulator padding, and pockets or cavities of air that can serve to feed an ignition source such as a candle, match, lighter, faulty electric socket, tipped over lamp or smoldering cigarette. For instance, pillow-top constructions feature additional layers of filling materials contained in layers on the panel surfaces, and set off aesthetically from the basic mattress design by gussets or seam lines in the case of the box-top approach. Gussets create thin lines of highly volatile fill materials and add more gaps and crevasses that can trap and concentrate heat and flame. A crowned/convex shape for the sleep surface or mattress panel also creates crevasses or voids between a mattress and foundation, again providing areas that can trap heat and flames and concentrates these on small areas. Also, the presence of a foundation does not provide an easy escape path for dissipation of heat across and beyond the bottom of the mattress. Super heating in the air cavity within the mattress and/or foundation can lead to what has been referred to as a flashover event.
One approach to reducing flammability of mattresses used in residential settings has been to treat fabrics used in their construction with chemical flame retardants. However, these chemical treatments may be objectionable because of distasteful odors which are noticeable when in close contact with the materials, off-gassing obnoxious elements, stiffness of the fabric caused by such treatments, which may compromise the comfort of the finished mattress or mattress foundation, and the potential temporary durability of such treatments, which may compromise the long term protection from open-flame, smoldering ignition and radiant/thermal heat flux sources. Other attempts to reducing flammability of fabrics have been only partly successful, and there are no materials commercially available for use in mattress that can reduce flammability of a sleep set including a mattress and foundation to a level where the requirements of TB 129 can be met.
For example, U.S. Pat. No. 4,504,991, to Klancnik, relates to a fire-resistant mattress that includes a flame-retardant composite. The composite is a two-layered material, made up of a flame-retardant material that forms a char when exposed to fire and a layer of high tensile strength material. The flammable materials of the mattress are enclosed by the composite. In the single embodiment disclosed, the composite is made up of a neoprene foam bonded to a fiberglass fabric.
U.S. Pat. No. 5,578,368, to Forsten, relates to a fire-resistant fiberfill material for use in sleeping bags, comforters, wearing apparel, upholstered furniture, and mattress tops. The material is composed of a fiberfill batt having little fire-resistance with an aramid fabric contacting the fiberfill layer.
U.S. Pat. No. 4,092,752, to Dougan, relates to a mattress enclosed with a flame-retardant polyurethane foam having an optional layer of polyimide foam.
U.S. Pat. Nos. 6,146,759 and 6,410,140, to Land, relate to a flame-retardant corespun yarn and fabrics incorporating them for applications such as mattress tickings.
Leggett and Platt, Inc. and Zoltek Companies, Inc. announced on Oct. 17, 2002 a family of fire-resistant products called PYRO GON(copyright) as an engineered blend of polyester and PYRON(copyright) fibers for use in mattresses and bedding. PYRON(copyright) is an oxidized polyacrylonitrile fiber.
However, none of these solutions is capable of imparting sufficient and consistent flame-retardant characteristics to the full breadth of styles and constructions of bedding typically used in the home, that is, a comfortable mattress placed atop a foundation, both containing a significant amount of flammable material. As a result, there is a need for new materials to protect residential mattress sets from fire, and especially for material in use in manufacturing mattress than can meet the more stringent flammability standards expected to be imposed on the residential market, such as TB 129.
It has been unexpectedly discovered that a composite flame retardant fabric, composed of a flame retardant fire barrier layer and a thermally insulating layer, can dramatically reduce flammability of a mattress or mattress set constructed therewith such a mattress or mattress set that is covered or partially covered with the composite fabric can meet the stringent new standards for flammability of mattresses and mattress sets for the residential market set by TB 129, and its equivalents.